Heretofore, as a planar pressure sensor for general use, there has been a pressure sensor in a mode of reading a resistance change caused by receiving compression, in which carbon particles are mixed into rubber. Besides this, there have been a pressure sensor in a mode where a mechanical or pneumatic pressure gauge is applied, and the like. However, in general, these pressure sensors have had some thickness and weight, and have been required to be additionally installed on a surface desired to be evaluated.
In consideration for these, as an example of a sensor using a piezoelectric material, which becomes capable of performing sensing in a lightweight/space-saving body, there is a piezoelectric fabric device described in Patent Document 1. This piezoelectric fabric device detects an electric signal that follows deformation of the piezoelectric material, thus becoming capable of performing the planar sensing. However, the piezoelectric fabric device uses the piezoelectric material, and accordingly, the signal obtained by the piezoelectric fabric device is generated as an instantaneous signal of a time of receiving force, and a continuous signal cannot be obtained. Therefore, static sensing information cannot be obtained. Moreover, the piezoelectric fabric device is formed by using, as warp yarns and/or weft yarns, piezoelectric fibers having a rectangular or flat cross-sectional shape, and accordingly, the number of sensing elements is limited by a width of the piezoelectric fibers, and detailed surface information exceeding such a piezoelectric fiber width cannot be obtained.
With regard to a multicomponent fiber, there is a multicomponent fiber capable of containing, as an additive, conductive fiber or particles such as graphite and activated carbon, which is described in Patent Document 2. However, the multicomponent fiber described in Patent Document 2 is merely a fiber capable of containing the conductive fiber or particles, and the pressure sensor or the actuator is not disclosed therein.
Patent Document 1: Japanese Patent Laid-Open Publication No. 2002-203996
Patent Document 2: Japanese Patent Application Publication No. 2005-503497